title: Aspergillus nidulans UDP-galactopyranose mutase, encoded by ugmA plays key roles in colony growth, hyphal morphogenesis, and conidiation.
abstract: Growing resistance to current anti-fungal drugs is spurring investigation of new targets, including those in fungal wall metabolism. Galactofuranose (Galf) is found in the cell walls of many fungi including Aspergillus fumigatus, which is currently the most prevalent opportunistic fungal pathogen in developed countries, and A. nidulans, a closely-related, tractable model system. UDP-galactopyranose mutase (UGM) converts UDP-galactopyranose into UDP-Galf prior to incorporation into the fungal wall. We deleted the single-copy UGM sequence (AN3112.4, which we call ugmA) from an A. nidulans nkuADelta strain, creating ugmADelta. Haploid ugmADelta strains were able to complete their asexual life cycle, showing that ugmA is not essential. However, ugmADelta strains had compact colonial growth, which was associated with substantially delayed and abnormal conidiation. Compared to a wildtype morphology strain, ugmADelta strains had aberrant hyphal morphology, producing wide, uneven, highly-branched hyphae, with thick, relatively electron-dense walls as visualized by transmission electron microscopy. These effects were partially remediated by growth on high osmolarity medium, or on medium containing 10 microg/mL Calcofluor, consistent with Galf being important in cell wall structure and/or function.
authors.affiliation: Department of Biology, University of Saskatchewan, 112 Science Place, Saskatoon, SK, Canada S7N 5E2.
authors.forename: Amira M
authors.initials: AM
authors.lastname: El-Ganiny
authors.forename: David A R
authors.initials: DA
authors.lastname: Sanders
authors.forename: Susan G W
authors.initials: SG
authors.lastname: Kaminskyj
mesh_terms: D001233:Aspergillus nidulans / Q000201:enzymology* / Q000254:growth & development*; D003470:Culture Media / Q000737:chemistry; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D025301:Hyphae / Q000254:growth & development / Q000648:ultrastructure; D019751:Intramolecular Transferases / Q000235:genetics / Q000502:physiology*; D046529:Microscopy, Electron, Transmission; D009024:Morphogenesis; D013172:Spores, Fungal / Q000254:growth & development
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D019751:Intramolecular Transferases; C098051:UDP-galactopyranose mutase